LeetCode-690. The importance of staff

Given a data structure stored employee information, it contains a unique id employees, and the importance of immediate subordinates id.

For example, the staff is 1 staff leadership 2, 2 employees employee leadership 3. The importance of their respective 15, 10, 5. Then the structure of employee data is [1, 15, [2]], employee data structure 2 is [2, 10, [3]] data structure, the staff is 3 [3, 5, []]. Note that though a subordinate employee staff is 3 1, but since not immediate subordinates, and therefore not reflected in the data structure of employees 1.

Now enter a company all the employee information, and a single employee id, and returns the employees of the importance of his subordinates and all.

Example 1:

Input: [[1, 5, [2, 3]], [2, 3, []], [3, 3, []]], 1
Output: 11
Explanation:
employee 1 importance degree itself is 5, he there are two immediate subordinates 2 and 3, and the importance of 2 and 3 are 3. Thus the overall importance of the employee is 5 + 3 1 + 3 = 11.
note:

An employee has a direct leading up to, but can have more immediate subordinate
number of employees does not exceed 2,000.
 

Source: stay button (LeetCode)
link: https: //leetcode-cn.com/problems/employee-importance
copyrighted by deduction from all networks. Commercial reprint please contact the authorized official, non-commercial reprint please indicate the source.

 

Analysis: 1, the importance of acquiring the target ID, but also the importance of acquiring a subsidiary, the most direct way is to traverse

 

Method 1: Using Recursive

public int getImportance(List<Employee> employees, int id) {
    if (employees == null || employees.size()==0) {
        return 0;
    }
    Map<Integer,Employee> map = new HashMap<>();
    //将员工信息放入 map 因为map的查找复杂度O(1)
    for (Employee e:employees) {
        map.put(e.id,e);
    }
    return getImportance(id,map);
}
public int getImportance(int eid,Map<Integer,Employee> map) {
    Employee employee = map.get(eid);
    int result = employee.importance;
    for (Integer subId: employee.subordinates) {
        result += getImportance(subId,map);
    }
    return result;
}

class Employee {
    // It's the unique id of each node;
    // unique id of this employee
    public int id;
    // the importance value of this employee
    public int importance;
    // the id of direct subordinates
    public List<Integer> subordinates;
};